The present invention relates to a sanitary toilet system for use in a recreational vehicle and in particular to such a system with an integral water supply and manual flush assembly for pumping flush water from the water supply to the toilet bowl for cleaning of the bowl.
In a recreational vehicle (RV) with a self-contained sanitary toilet system having its own flush water supply tank, it is necessary to provide a means for pumping water from the tank to the toilet bowl. Electric pumps have been employed which are easy to use by merely actuating an electrical switch to turn the pump on and off. However, electric pumps are expensive. Low cost manual pumps have also been used with the most common manual pump being a bellows pump. A bellows pump has a collapsible bellow forming a water chamber, and an inlet and an outlet, each with a check valve. When the bellows is compressed, it pushes water from the bellows past the outlet check valve. Upon subsequent expansion of the bellows, water is drawn into the chamber through the inlet check valve. The bellows, in its rest position, is expanded and projects from the housing upon which it is mounted. The bellows must project from the housing so as to be free from obstructions which would hinder its use. Because the bellows has no internal structure which guides the motion of the bellows upon compression, the maximum size of the bellows is limited to enable easy operation without buckling upon compression. As a result, the pump volume per compression is limited. Another disadvantage with a bellows pump is the relatively high force required for pumping.
It is an object of the present invention to provide a sanitary toilet system having an integral water supply with a manual flush pump which is low in cost, has high volume and requires relatively low pumping efforts.
The toilet system of the present invention includes a manually operated piston pump which is disposed within the flush water supply tank. A handle connected to one end of a piston rod extends from the tank for grasping by a user. The piston is not sealed to the pump cylinder. A clearance between the piston and cylinder produces a small annular space surrounding the piston. This space reduces the force required to operate the pump by avoiding a tight seal between the piston and cylinder. The force required to pump water is significantly less than the force required with a bellows pump. The pumping volume is determined by the stroke and diameter of the piston and can be easily be designed with a greater volume than is possible with a bellows pump. The clearance between the piston and cylinder is large enough that some of the water in the cylinder escapes movement out of the cylinder by flowing past the piston as the piston moves toward the discharge outlet. This reduces the pump efficiency measured by the ratio of the volume of water displaced to the cylinder volume. However, even with this reduced efficiency, the overall pump performance is improved with respect to a bellows pump.
In a preferred embodiment of the sanitary toilet system, a flush water tank is mounted within the body of the recreational vehicle adjacent to an upright wall of the vehicle body. The flush water tank has a fill neck that extends through the body side wall to enable convenient filling of the tank from the exterior of the recreational vehicle. By placing the tank adjacent to the RV side wall, there is no need for pipes in the vehicle from a water inlet to a remotely positioned tank.
Further objects, features and advantages of the invention will become apparent from a consideration of the following description and the appended claims when taken in connection with the accompanying drawings.